Decanter centrifuge system for producing low moisture solids from poultry plant sludge

ABSTRACT

In described embodiments, a system of processing poultry plant dissolved air floatation (DAF) float includes a horizontal decanter centrifuge having a weir ring. In conjunction with operating the centrifuge with a laminar flow, adjusted feed rate and polymer dosing, the system allows for production of low moisture solids (&lt;50%) from the poultry plant DAF float and discharge of a clear liquid phase.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.provisional application No. 62/569,195, filed on Oct. 6, 2017, theteachings of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to use of waste solid reclamation frompoultry plant waste and, more specifically, use of a decanter centrifugefor producing low moisture solids from poultry processing wastewater.

Description of the Related Art

A variety of wastewater treatment practices are utilized throughout thepoultry processing industry. However, a prevalent approach to wastewaterpretreatment in the poultry processing industry is the utilization ofdissolved air flotation systems (“DAF systems”) augmented with variouschemicals (e.g. polymers to enhance flocculation and others to managepH, etc.). DAF systems are used for the reduction of biochemical oxygendemand (BOD), total suspended solids (TSS) and fat, oil and grease (FOG)to comply with regulatory discharge requirements prior to the dischargeof wastewater streams to governmental wastewater treatment systems.

The primary components of a typical DAF system are sludge pumps,chemical feed equipment (to apply polymers, etc.), an air compressor, acontrol panel, and a flotation unit. In the operation of a DAF, influententers near the tank bottom and exits from the base at the opposite end.Flotation aids (e.g. polymers) are introduced in a mixing chamber at thetank inlet. Float is continuously swept from the liquid surface anddischarged over the end wall of the tank. Effluent is recycled at a rateof 30-150% of the influent flow through an air dissolution tank to thefeed inlet. In this manner, compressed air at 700-1000 kPa is dissolvedin the return flow. After pressure release, minute bubbles with adiameter about 80 micrometers form and attach to solid particles andbecome enmeshed in sludge flocs, floating them to the surface (“DAFfloat”). The DAF float is then skimmed from the surface of thewastewater and collected in float tanks for disposal, the primary methodof which is currently sub-soil injection.

Without the addition of polymers, solids capture might range from70-90%. However, removal efficiency increases to an average of 97%, witha polymer dosage of approximately 4.5 kg/t of dry suspended solidsbecause most DAF systems use flotation aids. A DAF system mighttypically reduce TSS and FOG by about 90 to 99%. In those wastewaterstreams in which the BOD is not solubilized into water, BOD can bereduced by up to about 75-85% and, in wastewater streams containing highlevels of soluble BOD, the reduction of soluble BOD may only be by about10-40% without chemical augmentation.

Consequently, DAF systems sometimes use chemical augmentation. Anexample of a system where chemical augmentation of a DAF system is thepoultry industry. Chemical augmentation of the DAF system is importantto the poultry industry to process the wastewater streams of poultrykill plants that contain blood solubilized therein. Poultry kill plantsprocess large numbers of live animals daily (i.e., a typical poultryplant processes 250,000 birds per day) and generate large volumes ofblood. A significant amount of such blood is solubilized into thewastewater stream and becomes a major element of soluble BOD in thestream.

Chemical augmentation of DAF systems might use Metal Salts Chemistry.Historically, the most commonly used treatment aid for addressingsolubilized BOD was ferric chloride, ferric sulfate or other metalsalts, at times aided by the pre-addition of an acid (Metal SaltsChemistry). When mixed with wastewater, Metal Salts Chemistry causes achemical reaction with the solubilized BOD. The Metal Salts Chemistrysufficiently lowers the pH of the wastewater stream to a typical targetrange of about 4.3-5.8 pH which facilitates precipitation/coagulation ofblood components in water. In some instances, the pH for DAF floatproduced with Metal Salts Chemistry is below about 4.3 pH. A significantportion of the BOD becomes insoluble and, therefore, is available to becaptured in the DAF float. In addition to being an effective wastewatertreatment aid, Metal Salts Chemistry is significantly less expensivecompared to other chemistries for reducing BOD. While Metal SaltsChemistry is effective at removing solubilized BOD from wastewaterstreams of poultry kill plants, this chemistry tends to create otherchallenges that appear in the DAF float itself. As an example, DAF floatproduced with Metal Salts Chemistry tends to retain more moisture thanDAF float produced with other chemistries as water tends to stay bondedmore tightly to the solids. The excessive moisture and increased weightmakes DAF float treated with Metal Salts Chemistry more expensive totransport and to further process (i.e., de-water) compared to DAF floatproduced with alternative chemistries.

The primary alternative to Metal Salts Chemistry (and which is currentlythe most popular) is treatment of wastewater in a DAF with one or morepolymers (“Polymer Chemistry”). In a poultry kill plant and breadingplant operations (i.e. where chicken is coated, seasoned and friedtypically in mixtures of soybean and/or canola oil), cationic polymers(which are positively charged and work best on biological material), incombination with other chemicals for pH control, etc., are used to catchthe organic particles in the wastewater stream. While more expensivethan Metal Salts Chemistry, Polymer Chemistry produces DAF float withless moisture content and lower water volume than DAF float produced byMetal Salts Chemistry, which might reduce the number of tanker loadsrequired to dispose of the DAF float. In addition, Polymer treated DAFfloat sometimes produces marginally higher oil recovery.

Given Metal Salts Chemistry and Polymer Chemistry, the resulting DAFfloat exhibits the following volume and other characteristics thateffect disposal of the DAF float. The issue of disposal of DAF Float iscomplicated in large part due to the sheer volume of DAF float producedby poultry kill plant and breading plant operations. While these plantsvary in size and operation, it is not unusual for example for a typicalU.S. poultry processing plant to produce in excess of 100,000 lbs. ofDAF float per day from a wastewater stream of approximately 1 milliongallons. Because of the large volume of water in the DAF float and theincreasingly stringent government regulations on its disposal, the costsassociated with DAF float disposal is very high. Specific Gravity Issuesarise because DAF float is generated through a process where theconstituent components of the DAF float (air/micro-bubbles, FOG,polymers and other solids taken out of solution) have a combined and/oroverall specific gravity of less than 1, which allows the float to riseto the top of the water in the DAF tank (since the specific gravity ofwater is 1). This characteristic of the DAF float has been the primaryproblem such operations have had in efficiently and effectively dryingthe solids in the float to the point that the costs associated withsub-soil injection could be eliminated. Moisture Content Issues arisebecause, on average, the DAF float from a kill plant or breading plantoperation might typically contain 80-90% moisture. In contrast, offalfrom a Poultry kill plant (e.g. the intestines and other parts of thebird not sold for human consumption) might contain an average ofapproximately 67% moisture.

The prevalent disposal method of DAF float is currently through sub-soilinjection. Historically, some processors land applied their DAF floatbut current environmental laws have virtually eliminated this practice.In addition to disposal through sub-soil injection or land application,some processors have attempted to process their DAF Float into materialfor incorporation into animal feed. Since the DAF float from kill plantscontains protein and fat (and that of breading plants contains oil,flour and, to a lesser extent, protein), processing the DAF Float to thepoint where renderers would purchase the DAF float solids forincorporation into animal feed is desirable. However, such attemptshave, for the most part, not met with success.

Among the first entities to propose resource and/or by-product recoveryas a method for eliminating DAF Float was Bird Environmental Systems andServices, Inc. (“BESS”). BESS's approach combined heating DAF float to180-200 degrees F. and then processing the heated float through a3-phase centrifuge. The objective of BESS's approach was to break downthe DAF float into its three principle components: water, solids andoil, and the water then sent to the wastewater treatment plant. Thesolids might be sold to a renderer (i.e. protein from a Kill Plant andcarbohydrates from a Breading Plaint) and the oil would have commercialvalue. BESS estimated that with their prescribed mode of operation theDAF float, on average, would be broken into the following constituents'parts: 90% water, 7% solids and 3% oil. Centrifuge equipmentmanufacturers will typically report that they can achieve 3-4% oilextraction by volume in DAF float produced by Metal Salts Chemistry andperhaps 5-6% in DAF float produced by Polymer Chemistry.

The primary reason centrifugation of DAF float has not become prevalentin the poultry and other food processing industries is that processorsand equipment vendors have not been successful in dewatering the floatto the point where the moisture content of the solids is low enough forrenderers to be willing to purchase and/or use the solids (forincorporation into animal feed) or, alternatively, pass a paint filtertest so the solids could at least be disposed of in a typical land fill.Moreover, given the characteristics of poultry DAF float, thecentrifuges, as configured, are unable to produce clarified water fordischarge from the centrifuges with sufficiently low moisture content.As a result, even where the processors are harvesting oil from their DAFfloat, the “high moisture” solids have to be pumped back into a DAFFloat collection tank for eventual sub-soil injection and/or landapplication. Under such a scenario, the processors are, at best,defraying a portion of their sub-soil injection and/or land applicationscosts through the sale of the harvested oil.

SUMMARY OF THE INVENTION

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

In one embodiment, sludge of a poultry processing plant is processedwith a sludge tank for containing the sludge, the sludge a dissolved airflotation system float (DAF float) treated with Polymer Chemistry; thesludge adjusted to a predetermined temperature range; a mixing tank toadd polymer into the heated sludge to produce a slurry; and a decantercentrifuge. The decanter centrifuge comprises a bowl and a scroll, thescroll passing through a central longitudinal axis of the bowl andincluding a weir ring, wherein the scroll and the bowl rotate about thelongitudinal axis in a same direction but with a differential rotationspeed so as to provide a laminar flow of slurry in the decantercentrifuge. Rotation of the scroll and the bowl centrifugally separatesthe slurry into solids and at least one liquid phase and collects thesolids on an inner surface of the bowl. The weir ring prevents solidsfrom mixing with the at least one liquid phase, and the rotation of thescroll in combination with the differential rotation speed moves thesolids from a cylinder section of the bowl toward a conical section ofthe bowl. The decanter centrifuge receives the slurry, provides thesolids at a corresponding discharge port of the conical section, andprovides the at least one liquid phase at a corresponding discharge portof the cylinder section, wherein the solids comprise 50% or lessmoisture content.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects, features, and advantages of the present invention willbecome more fully apparent from the following detailed description, theappended claims, and the accompanying drawings in which like referencenumerals identify similar or identical elements.

FIG. 1 shows a waste solid reclamation system in accordance with anexemplary embodiment;

FIG. 2 shows an exemplary embodiment of decanter centrifuge for use withthe centrifuge with weir system of FIG. 1; and

FIG. 3 shows an exemplary method of processing sludge of a poultryprocessing plant into solids.

DETAILED DESCRIPTION

In accordance with described embodiments, a system and method for wastesolid reclamation from poultry plant waste includes a decantercentrifuge incorporating a weir for producing low moisture solids frompoultry processing wastewater.

FIG. 1 shows waste solid reclamation system 100 in accordance with anexemplary embodiment. Waste solid reclamation system 100 comprises DAFsludge tank 102 to receive dissolved air flotation (DAF) system float(“DAF float”), optional heat tank 104, mixing tank 106, and centrifugewith weir system 108. Pumps 103, 105 and 107 represent pumps employed tomove the various forms of processed slurry along the path from DAFsludge tank 102 to centrifuge with weir system 108. A poultry kill plantor a poultry breading plant generally produces DAF float (also referredto as DAF sludge) for processing by waste solid reclamation system 100into solids or cake (hereinafter “solids”). In addition, waste solidreclamation system 100 provides oil and water as a result of theseparation of solids from the DAF float.

Waste solid reclamation system 100 employs centrifuge with weir system108. Centrifuge with weir system 108 comprises a decanter centrifugehaving a weir in accordance with exemplary embodiments as describedsubsequently, as well as other components, such as devices to heat,press and further dry output solids, filters to clarify the liquids andoils, and other device known in the art for operation and safety (e.g.,computers, sensors, etc.). FIG. 2 shows an exemplary embodiment ofdecanter centrifuge 200 for use centrifuge with weir system 108 of FIG.1.

Decanter centrifuge 200 generally comprises an outer bowl 201 formed byneck section 202, conical section 203, cylinder section 204 and rear(end cap or wall of cylinder section) 206. A diameter of neck section202 is less than a diameter of cylinder section 204, with conicalsection 203's diameter varying from between that of neck section 202 andcylinder section 204 to form the transition between neck section 202 andcylinder section 204.

Decanter centrifuge 200 further comprises an interior rotatingscrew-conveyor (“scroll”) 210, slurry feed 222 for providing slurry ontoscroll exterior of 210 to be processed, and discharge ports 224 and 226.Scroll 210 is formed by wall 211 extending radially from and spiralingalong hub 212. Decanter centrifuge 200 further comprises an internalstructure 213, referred to herein as a “weir ring” described in detailsubsequently, formed at the end of scroll 210 and adjacent to rear 206of cylinder section 204.

Slurry is provided from collection area 220 at neck section 202 into theinterior of scroll 310 through hub 212 for output from slurry feed 222,where slurry feed 222 is provided as an opening in hub 212. Althoughshown as entering at neck section 202, in alternative embodiments slurrymight be collected and passed into the interior of scroll 210 for outputfrom slurry feed 222 by entering through the hub 212 at rear 206. Slurryfeed 222 is generally positioned in the center of decanter centrifuge200 in hub 212, and adjacent to the border between conical section 203and cylinder section 204. Bowl 201 includes cylindrical section 204where clarified water is discharged from discharge port 226, and conicalsection 203 where solids are discharged from discharge port 224.

In operation, outer bowl 201 of decanter centrifuge 200 rotates about alongitudinal axis, the bowl being provided with a solids dischargeopening at the conical end of the bowl and a liquid phase(s) dischargeopening at the opposite (cylindrical) end as described above. Forexemplary embodiments, bowl 201 might be rotating at about 2400revolutions per minute (RPM) about a longitudinal axis. Scroll 210 isdisposed inside of bowl 201 for rotation about the longitudinal axis ata differential speed from that of bowl 201, which rotation might be lessthan 2400 RPM to create the differential. Scroll 210 is rotated so as toconvey the deposited solids layer along the inner surface (or wall) ofbowl 201 towards the solids discharge opening(s). As shown, the feedelement extends into the scroll hub for delivering a feed slurry into apool inside the bowl at approximately the center of the bowl. Bowl 201and scroll 210 inside bowl 201 are both rotated at relatively highspeed, but with different speeds by motor (drives, hydraulic assembly,etc.) 230 so that heavier solid particles (those with a specific gravityof greater than one) of input slurry introduced into the bowl are forcedby centrifugation into a layer along the inner surface of bowl 201.Through the differential rotation of scroll 210 and bowl 201, the solidsare conveyed by action of rotating, spiral wall 211 toward dischargeport 224 at the conical end of the bowl (e.g., conical section 203).Additional discharge openings are provided at the cylindrical end (e.g.,cylinder section 204) of the bowl near rear 206 for discharging theliquid phase(s) that are separated from the solids that collect withincylinder section 204 at discharge port 226.

Weir ring 213 is provided which extends radially outwardly from hub 212of scroll 210 towards the inner surface of bowl 201 that extends fromthe longitudinal axis of the scroll to a position (“height”) slightlybelow an outside diameter of scroll 210, which for described embodimentsis the approximately ¼″-½″ below the outside diameter of the scroll. Ingeneral, the height of the weir ring from the longitudinal axis of thescroll is dependent upon the percentage of solids in the feed for agiven application. Weir ring 213 is generally closely positionedadjacent to rear 206. For described embodiments employing a DDSDecanter-Type-K652MC, the weir ring is placed approximately 6″ inchesfrom the cylindrical end of the bowl (depending on the length of thebowl) to trap the low density solids (generated from the production ofpoultry DAF float) for transmission to the conical end of the centrifugefor discharge through the solids discharge port. Depending on theembodiment, the position of the weir ring might be adjusted towards theslurry feed inlet to allow for three phase operation of the centrifuge,where liquid phases are further separated into water and oil.

The DAF float has a combined specific gravity of less than 1, and,therefore, because of its low density, causes flocs to float on thewater and any oil in the float (rather than settling to the bowl) and sobeing easily drawn down to the conical end of the centrifuge by thescroll and discharged. The weir ring “traps” the flocs so they aregenerally not discharged with the liquid phase(s) at the cylindrical endof the bowl. In developing the exemplary embodiments, a DDSDecanter-Type-K652MC was modified to include the internal structurecomprising the weir ring to capture the low density solids fortransmission to the solids discharge port at the conical end of thebowl.

The design of a decanter centrifuge in accordance with exemplaryembodiments of the present invention generally depends on the size ofthe poultry plant and volume of slurry produced. However, the inventorhas determined that the dimensions and relationship between dimensionsof components of the decanter centrifuge for an embodiment might scaleup or scale down linearly. An exemplary set of dimensions for a decantercentrifuge that is relatively small might be as follows: length ofcentrifuge is approximately 51¼″, diameter of hub of scroll isapproximately 7½″, outer diameter of scroll is approximately 16½″, pitchof screw formed by wall on scroll is approximately 5″, diameter of weirring is approximately 16¼″, inside diameter of the outer bowl is 16¾″,and distance of weir ring to rear of cylinder is 15/16″ to 1⅞″.

Returning to waste solid reclamation system in accordance with theexemplary embodiment of FIG. 1, operation of decanter centrifuge 200 ofFIG. 2 requires chemical conditioning of the slurry applied to slurryfeed 222. Since poultry DAF float is comprised of biological material,processors utilize Polymer Chemistry and use cationic polymers in thepoultry DAFs. From DAF sludge tank 102, the DAF float is pumped (by pump103) through a heat exchanger of optional heat tank 104, heating(usually by steam) the DAF float to between 35-50 degrees Celsius (95 to122 degrees Fahrenheit). Heat tank 104 is shown as optional since thetemperature of the sludge might vary depending upon environment of thepoultry plant producing the sludge. In some plants (for example, in theSouthern United States) the general temperature might be high enough notto require heating, while a plant in the northern United States mightrequire heating. Other embodiments might require cooling of the sludge,in which case the heat tank would operate a heat exchanger in reverse.In general, heat tank 104 represents an operation to producetemperature-adjusted DAF float for proper operation of polymer additionand centrifugal separation by decanter centrifuge 200.

The temperature-adjusted DAF float from heat tank 104 is then pumped (bypump 105) into mixing tank 106 to dose (usually) with the same cationicpolymer used to generate the DAF float to minimize chemical costs. Forthe described embodiment, the cationic polymer used to develop theoperation was DS801 FG, purchased from Dolphin Services and Chemicals,LLC.

Pump 107 is used to transport the slurry to decanter centrifuge 200 viainlet pipe 110. After the DAF float is heated and mixed with cationicpolymer to dose the slurry, preferably cationic polymer is injected atthe inlet pipe 110 after feed pump 107 from mixing tank 106 to avoidshear. The polymer feed line is preferably approximately 10′-15′ fromthe feed inlet (e.g., collection area 220 of FIG. 2) of the decantercentrifuge (e.g., decanter centrifuge 200) or a static mixer (not shownin the FIGS.) used to allow sufficient time for the polymer to activateand tighten the binding of the substrates of the flocs. The processdescribed between mixing tank 106 and chemical conditioning of theslurry applied to slurry feed 222 is adjusted depending on the specificembodiment to provide a feed rate through slurry feed 222 for nearoptimal performance of separation of the slurry into solids and liquidphases by decanter centrifuge 200.

Temperature is an important factor that impacts float conditioning,optimum polymer dose, and thickening/dewatering performance. Since theconstituent components of poultry DAF float are not homogenous (e.g.there are obviously differences between poultry kill plant and poultrybreading plant DAF float, but differences also exist within each ofthese types of DAF float at any given time), the exact dosage of polymerwill vary. However, for the described embodiment, near optimalperformance might be achieved at approximately 50 degrees Celsius at apolymer dose of approximately 19.2 g/kg DS. (See, for example, “Effectof Sludge Conditioning Temperature on the Thickening and DewateringPerformance of Polymers”, Journal of Residuals Science & Technology,Vol. 13, No. 3—July 2016). Increasing the float temperature to 60degrees Celsius or higher increases the polymer demand up to 38.5 g/kgDS and deteriorates the thickening and dewatering performance. Manycationic polymers are generally recognized as safe for animal ingestionthat, therefore, allows the solids to be incorporated into animal feed.

The use of the weir ring, in conjunction with i) operating the decantercentrifuge with a laminar flow and ii) adjusting the feed rate andcationic polymer dosing as described herein, allows for the productionof low moisture solids from the processing of poultry DAF float anddischarge of a clear liquid phase. Once near optimal operatingparameters are achieved for a given embodiment at a given poultryprocessing plant, solids might be produced with a moisture content wellless than 50%. As a result, the solids might be available to renderers(in the case of poultry kill plant solids produced with PolymerChemistry), for the protein and residual oil value and, (in the case ofBreading Plant solids), for the carbohydrate and residual oil value or,alternatively, disposed of at a typical land fill. Whether the processdescribed herein is used at a poultry kill plant or poultry breadingplant, use of the described embodiments avoids use costly sub-soilinjection for waste solids disposal.

In addition to the production of low moisture solids, the fat, in thecase of poultry kill plant DAF float, and the combination of oils,typically soybean and/or canola oil, in the case of a poultry breadingplant, might also be harvested through a variety of measures including,but not limited to, using a three phase centrifuge (modified with aninternal structure including a weir ring as described herein), naturallyallowing the liquid phases (oil and water) to separate in a collectiontank after discharge from the centrifuge and/or using chemicallyenhanced fat and/or oil extraction prior to polymer dosing into the feedline of the centrifuge.

The exemplary embodiments produce waste solids with a low moisturecontent, generally less than 50%, which is sufficient to pass a “paintfilter” test well-known in the art. In a paint filter test, the solidsare provided to a filter with holes having a specified hole-diameterand, to pass the test, should be captured by the filter. In connectiontherewith, various methods have been proposed that involve the additionof structures within the bowl to exert pressure on the solids as theyare conveyed to the conical end of the bowl for discharge to reducemoisture content even further. See, for example, U.S. Pat. No.5,695,442, titled “DECANTER CENTRIFUGE AND ASSOCIATED METHOD FORPRODUCING CAKE WITH REDUCED MOISTURE CONTENT AND HIGH THROUGHPUT, toLeung et al., filed Jan. 31, 1996, issued Dec. 9, 1997, the teachings ofwhich are incorporated herein in their entirety by reference, for adiscussion of such structures, which primarily involve adding internalstructures proximate to the solids discharge ports.

In conjunction with the addition of the weir ring, variable frequencydrives (e.g., variable frequency drive for motors 230 of FIG. 2) allowfor the adjustment of the speed of the bowl and sludge feed rate, aswell as a hydraulic back drive to control the speed of the scroll forthe bowl and scroll drive system used to create near optimal speeddifferential for the implementation of the described embodiment. To makeeffective and efficient use of the weir ring, the scroll and bowldifferential is reduced to the point that a laminar flow is present(rather than a turbulent flow) inside the centrifuge so the solids,which due to the constituent components thereof (including any oiland/or air trapped in the float) have a specific gravity of less than 1,might be separated from the liquid phase, with the solids being conveyedto the inner surface of the conical section (sometimes referred to inthe art as the “beach” of the centrifuge) and discharged through thesolids discharge port(s).

The differential rotation speed between the scroll and bowl required tocreate a laminar flow in connection with the processing of poultry DAFfloat was approximately 8-15 RPMs in the described embodiment for aslurry produced by a poultry kill plant. The differential is adjusted asneeded, in conjunction with the slurry feed rate, to attain a laminarflow so that the liquid phase(s) have little or no low density solidscontained therein.

For a poultry processing plant where breading and/or cooking takes place(i.e., a breading plant where slurry is comprised primarily of oil,flour and muscle tissue (raw and cooked)), the described embodimentmight vary as follows. The differential rotation speed between thescroll and bowl might be less for a poultry breading plant: for example,approximately 6-8 RPMs, which is lower than 8-15 RPMs for slurrygenerated by a poultry kill plant (comprised primarily of fat, blood andraw muscle tissue). Moisture content attributable to water might be onthe order of 47.2%. While 47.2% might be higher than is achieved withthe poultry kill plant embodiment, moisture content is below 50%, whichis required to pass the paint filter test, the described process hereinproduces dried solids with a moisture content (in relation to bothkill/breading/cooking plant sludge) less than that coming off a DAFfloat, which is usually in the 80-90% moisture content range.

FIG. 3 shows an exemplary method 300 of processing sludge of a poultryprocessing plant into solids. At step 302, the sludge is stored in asludge tank, the sludge a dissolved air flotation system float (DAFfloat) treated with Polymer Chemistry. At step 304, a heat tankoptionally heats or otherwise temperature-adjusts the sludge from thesludge tank to a predetermined temperature range as generally describedherein. At step 306, a mixing tank is employed to add polymer by dosingto the heated sludge, and additional polymer is injected (whilepreventing shear) via an inlet pipe to produce a slurry. At step 308,the decanter centrifuge, incorporating the weir ring as described forthe exemplary embodiments, separates the slurry into the solids and atleast one liquid phase (e.g., oil and water). Step 308 includes step310, rotating the scroll and the bowl about the longitudinal axis in asame direction, but with a differential rotation speed, providing alaminar flow of slurry in the decanter centrifuge. Step 308 furtherincludes step 312, rotating the scroll and the bowl centrifugallyseparating the slurry into the solids and the at least one liquid phase,thereby collecting the solids on an inner surface of the bowl, with theweir ring preventing solids from mixing with the at least one liquidphase, and the rotating the scroll in combination with the differentialrotation speed moves the solids from a cylinder section of the bowltoward a conical section of the bowl. Step 308 further includes step314, providing the solids at a corresponding discharge port of theconical section, and providing the at least one liquid phase at acorresponding discharge port of the cylinder section, wherein the solidscomprise 50% or less moisture content.

Reference herein to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment can be included in at least one embodiment of theinvention. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment, nor are separate or alternative embodiments necessarilymutually exclusive of other embodiments. The same applies to the term“implementation.”

As used in this application, the word “exemplary” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects or designs. Rather, use ofthe word exemplary is intended to present concepts in a concretefashion.

Additionally, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

Although the subject matter described herein may be described in thecontext of illustrative implementations to process one or moreapplication features/operations, the subject matter is not limited tothese particular embodiments. Rather, the techniques described hereincan be applied to any suitable type of user-interactive componentexecution management methods, systems, platforms, and/or apparatus. Thepresent invention can be embodied in the form of methods and apparatusesfor practicing those methods.

Unless explicitly stated otherwise, each numerical value and rangeshould be interpreted as being approximate as if the word “about” or“approximately” preceded the value of the value or range.

The use of figure numbers and/or figure reference labels in the claimsis intended to identify one or more possible embodiments of the claimedsubject matter in order to facilitate the interpretation of the claims.Such use is not to be construed as necessarily limiting the scope ofthose claims to the embodiments shown in the corresponding figures.

It should be understood that the steps of the exemplary methods setforth herein are not necessarily required to be performed in the orderdescribed, and the order of the steps of such methods should beunderstood to be merely exemplary. Likewise, additional steps may beincluded in such methods, and certain steps may be omitted or combined,in methods consistent with various embodiments of the present invention.

As used herein in reference to an element and a standard, the term“compatible” means that the element communicates with other elements ina manner wholly or partially specified by the standard, and would berecognized by other elements as sufficiently capable of communicatingwith the other elements in the manner specified by the standard. Thecompatible element does not need to operate internally in a mannerspecified by the standard.

Further, the term “comprises or includes” and/or “comprising orincluding” used in the document means that one or more other components,steps, operation and/or existence or addition of elements are notexcluded in addition to the described components, steps, operationand/or elements.

No claim element herein is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or “step for.”

It is understood that various changes in the details, materials, andarrangements of the parts which have been described and illustrated inorder to explain the nature of this invention may be made by thoseskilled in the art without departing from the scope of the embodimentsof the invention as encompassed in the following claims.

I claim:
 1. Apparatus for processing sludge of a poultry processingplant, the apparatus comprising: a sludge tank for containing thesludge, the sludge a dissolved air flotation system float (DAF float)treated with Polymer Chemistry, the sludge adjusted to a predeterminedtemperature range; a mixing tank to add polymer into the sludge toproduce a slurry; and a decanter centrifuge coupled to receive theslurry and comprising a bowl and a scroll, the scroll passing through acentral longitudinal axis of the bowl and including a weir ring, whereinthe scroll and the bowl rotate about the longitudinal axis in a samedirection but with a differential rotation speed so as to provide alaminar flow of slurry in the decanter centrifuge, and wherein rotationof the scroll and the bowl separates the slurry into solids and at leastone liquid phase and collects the solids on an inner surface of thebowl, the weir ring configured to prevent the solids from mixing withthe at least one liquid phase, and the rotation of the scroll incombination with the differential rotation speed moves the solids from acylinder section of the bowl toward a conical section of the bowl,wherein the weir ring (i) extends radially outwardly from a hub of thescroll towards an inner surface of the bowl, and (ii) extends from thelongitudinal axis of the scroll to a position below an outside diameterof scroll, the weir ring positioned adjacent to a rear of the cylindersection of the bowl, in front of one or more discharge ports of thecylinder section of the bowl, and opposite to the conical section of thebowl; and wherein the decanter centrifuge receives the slurry, providesthe solids at a corresponding discharge port of the conical section, andprovides the at least one liquid phase at a corresponding one of the oneor more discharge ports of the cylinder section, wherein the solidscomprise 50% or less moisture content.
 2. The apparatus of claim 1,wherein: the mixing tank is coupled to the decanter centrifuge via aninlet pipe; the mixing tank is configured to receive and to dose thesludge with polymer; and the inlet pipe is configured to receiveadditional polymer and configured to inject the additional polymer intothe dosed sludge to produce the slurry.
 3. The apparatus of claim 1,wherein, for the decanter centrifuge: the bowl having a neck section,the conical section positioned and transitioning between the necksection and the cylinder section, and the hub of the scroll receives theslurry at the neck section, the slurry passing through the inside of thehub to an output slurry feed positioned inside the bowl.
 4. Theapparatus of claim 1, wherein the poultry processing plant is a poultrykill plant.
 5. The apparatus of claim 4, wherein the differentialrotation speed between the scroll and the bowl is between approximately8-15 revolutions per minute (RPMs).
 6. The apparatus of claim 1, whereinthe poultry processing plant is a poultry breading plant.
 7. Theapparatus of claim 6, wherein the differential rotation speed betweenthe scroll and the bowl is between approximately 6-8 revolutions perminute (RPMs).
 8. The apparatus of claim 1, wherein the at least oneliquid phase includes oil and water.
 9. A decanter centrifuge configuredto process slurry derived from sludge of a poultry processing plant, thesludge a dissolved air flotation system float (DAF float) treated withPolymer Chemistry, the decanter centrifuge comprising: a bowl; and ascroll passing through a central longitudinal axis of the bowl, the bowlhaving a neck section, a cylinder section having a rear, and a conicalsection positioned and transitioning between the neck section and thecylinder section, the scroll passing through the neck section, thecylinder section, and the conical section, and the scroll having a weirring that (i) extends radially outwardly from a hub of the scrolltowards an inner surface of the bowl, and (ii) extends from thelongitudinal axis of the scroll to a position below an outside diameterof scroll, the weir ring positioned adjacent to the rear of the cylindersection of the bowl, in front of one or more discharge ports of thecylinder section of the bowl, and opposite to the conical section of thebowl; the hub of the scroll configured to receive the slurry, the slurrypassing through the inside of the hub to an output slurry feedpositioned inside the bowl; wherein the scroll and the bowl rotate aboutthe longitudinal axis in a same direction with a differential rotationspeed configured to provide a laminar flow of slurry in the decantercentrifuge, and wherein rotation of the scroll and the bowl isconfigured to separate the slurry into solids and at least one liquidphase and collect the solids on an inner surface of the bowl, the weirring configured to prevent the solids from mixing with the at least oneliquid phase, and the rotation of the scroll in combination with thedifferential rotation speed moves the solids from the cylinder sectiontoward the conical section; and wherein the decanter centrifuge isconfigured to provide the solids at a corresponding discharge port ofthe conical section and provide the at least one liquid phase at acorresponding one of the one or more discharge ports of the cylindersection, wherein the solids comprise 50% or less moisture content. 10.The decanter centrifuge of claim 9, wherein the poultry processing plantis a poultry kill plant.
 11. The decanter centrifuge of claim 10,wherein the differential rotation speed between the scroll and the bowlis between approximately 8-15 revolutions per minute (RPMs).
 12. Thedecanter centrifuge of claim 9, wherein the poultry processing plant isa poultry breading plant.
 13. The decanter centrifuge of claim 12,wherein the differential rotation speed between the scroll and the bowlis between approximately 6-8 revolutions per minute (RPMs).
 14. Thedecanter centrifuge of claim 13, wherein the at least one liquid phaseincludes oil and water.